1. Field of the Invention
The present invention relates to a III-nitride semiconductor laser device, and a method for fabricating the III-nitride semiconductor laser device.
2. Related Background Art
Non-patent Literature 1 describes a semiconductor laser made on a c-plane sapphire substrate. The mirror faces of the semiconductor laser are made by dry etching. It shows micrographs of the cavity mirror faces of the laser and describes that the roughness of the end faces is about 50 nm.
Non-patent Literature 2 describes a semiconductor laser made on a (11−22)-plane GaN substrate. The mirror faces of the semiconductor laser are formed by dry etching.
Non-patent Literature 3 describes a gallium nitride (GaN)-based semiconductor laser. It proposes generation of laser light polarized in an off direction of the c-axis of the substrate, in order to use m-planes of cleaved facets for the laser cavity. Specifically, this Literature describes increase of the well thickness on a nonpolar surface and decrease of the well thickness on a semipolar surface.    Non-patent Literature 1: Jpn. J. Appl. Phys. Vol. 35, (1996) L74-L76    Non-patent Literature 2: Appl. Phys. Express 1 (2008) 091102    Non-patent Literature 3: Jpn. J. Appl. Phys. Vol. 46, (2007) L789